January 4th, 2008
Keywords in languages
It’s nice to see how the amount of people looking into Scala has really exploded lately, based on the rush of blog posts an discussion.
One of the things I find a bit annoying about Scala is the proliferation of keywords. Actually, this is something I really don’t like in any languages. A language should be as keywordless as possible. Of course, such a vision goes against ease of implementation for language implementers, so there always needs to be a balance here. Coming from languages such as Lisp and Io, it’s amazing how clear a language can be with a well chosen message passing or invocation model. In fact, both of those languages have zero keywords. That makes it incredibly nice to implement whatever you want.
Actually, Java has been quite good at not taking much more keywords than they had from the beginning, so I found it a bit annoying when I tried to build a fluent interface in Scala, and found out that the word “with” is a keyword. And it’s a keyword in the strictest sense, meaning you can’t use it in places where you can’t use the “with” keyword anyway. So there is no way to implement a method named “with” in Scala. Annoying. It’s just, the English connection words are so much more useful for method names, especially when you can use the methods in “operator” position. Then you just want to be able to use all these words.
So. If you design a language, make sure that you take care to actually add every keyword extremely carefully. If you can, make sure that keywords can actually be used for some things when there is no ambiguity. Of course, I’m not proposing the kind of madness you can do in some languages, where a statement such as “IF IF THEN THEN” is valid, since the first IF is a keyword, the next is a variable name, etc. But be reasonable about keywords. They are sometimes necessary, but not always as often as people believe.
